The invention relates to an x-ray diagnostic system with an image intensifier television chain, a dose rate control means for fluoroscopy for maintaining the mean image intensity constant during a fluoroscopic examination via a fluoroscopic parameter, and with an automatic exposure control with an integrator for the formation of a signal corresponding to the respective x-ray dose per image, said signal effecting the shutdown of the x-radiation via a switching stage when a prescribed dose value is reached, as well as with means for setting the exposure x-ray tube voltage as a function of the patient transparency.
An x-ray diagnostic system of this type is described in the German AS 19 29 894 and in the corresponding U.S. Pat. No. 3,546,461 issued Dec. 8, 1970. Given this x-ray diagnostic system, when a prescribed time window for the exposure time of an x-ray exposure is fallen below or exceeded, the x-ray tube voltage is influenced in such manner that the exposure time of the image following an adjustment operation again lies within the limits prescribed by the time window. Said publication states nothing concerning the setting of the further exposure values, particularly of the x-ray tube output, and concerning the overload protection of the x-ray tube.